Cartridge



July 24, 1928. 1,678,162

J. D. PEDERSEN CARTRIDGE Filed May 20, 1926 Mo; D 7

I INVENTOR.

A TTORNEYS.

Patented July 24, 1928.

FIQE- 7 JOHN D. PEDERSEIL'OF SPRINGFIELD, MASSACHUSETTS.

CARTRIDGE.

Application filed May 20,

This invention relates to improvements in cartridges for fire arms and amethod of rendering the same more durable and serviceable.

More particularly, the invent-ion aims to improve a cartridge in twomain respects: first, to provide a weatherproof protective coat-ing forthe cartridge which will enable "it to be stored without deteriorationfor longer periods of time than heretofore; and second, to provide ameans of lubrication for the cartridge to facilitate its extraction fromthe chamber of the fire arm when fired As regards the feature ofproviding a protective coating for the cartridge, one of the principalcauses for deterioration of cartridges in storage is that they aresubject to what is known as season crackinglf By this it is meant thatthe metal case or shell of the cartridge after a time will develop abreak or crack which usually starts around the thinnest part of themetal at the mouth or neck of the case and works backwardly toward thebase. This season cracking is presumably due to the unrelieved strainsin the metal of the case which have beenset up during the drawing andannealing of the same in its manufacture. Obviously any weakening of thethin metal composing the case by corrosion or other destructive weathereffects will accelerate the occurrence of theaforesaid season cracking.I have found that if the metal case is well protected from moisture andactionof the atmosphere that the time of season cracking may bepostponed and thereby the life of the cartridge in storage greatlyprolonged. I have also found that such a suitable protective coating maybe, furnished by certain of the hardiwaxes of commerce and further thatby selecting for this purpose a wax of the 'proper characteristicscertain other very desirable advantages will flow from its use as willnow be mentioned.

It has long been recognized that me quick firing fire arm, the.extraction of the empty cases becomes increasingly 'diflicult as the gunbecomes heated through repeated firing. This may be in large part due tothe fact that during the first shot or two the chamber of the guncontains suflicient lubricant to make extraction of the case easy,'butwhen this lubricant is burned off or otherwise destroyed, the extractionbecomes more l w t a eus attempts have been ma e 1926. Serial No.110,559.

to lubricate cartridges as they. are introduced into the chamber of thegunin order to make the extraction of the empty cases more uniformthroughout a period of continued rapid fire. Such methods necessitatethe provision of lubricating devices in the. gun and demand someattention and care on the part of the gun operator. By the presentinvention, the means for lubrication are provided on the cartridge whenmanufactured, which both simplifies the solution of the problem and alsorequires no cooperation from the user of the gun.

I have found that a properly selected hard wax may serve both for theprotective covering for the cartridge above mentioned and also when thecartridge is fired it will be melted by the heat and pressure so as toserve as a lubricant in rendering the extraction of the empty case easyand uniform.

The most suitable wax which I have found for the purposes named andwhich I at present prefer is ceresin, a refined product of ozokerite;but I wish to have it understood, of course, that other waxes havingsimilar qualities may exist which might serve equally well. Someof thecharacteristics of ceresin which render it so desirable for the purposesin view are that it is hard and non-tacky at normal temperatures,melting somewhere between C. to 80 C. and therefore will not soften ormelt under any weather condition to which it is subjected, even that ofextreme tropical heat. It is chemically stable to the action of mostreagents, at least such as are found in the atmosphere. When hard itforms a strongly adherent coating which will not flake oil or brush oileasily and has a smooth glassy surface which is not greasy or acollector of dust. It may be applied in a very thin transparent film,hardly perceptible vto the eye, so that the condition of the metalliccase beneath it can at alltimes be inspected.

In the drawing which shows a preferred embodiment of the invention:

Fig. 1 illustrates a complete cartridge, half in section'and half inelevation.

1 indicates the metallic case or shell of the cartridge with itsconically tapered shoulder'at 2, cylindrical neck 3 and mouth 4 intowhich the bullet 5 is secured. 6 indicates the powder charge and 7 theprimer.

Preferably over substantially the entire surface of the cartridge istopped. a thin coating of hard Wax, preferably ceresin as indicated at8. It will be understood that the drawing necessarily exaggerates thethickness of said Wax coating 8 in order to illustrate the same. Inactual practice, the

coating is less than a thousandth of an inch thick. In other Words, thethickness of the coating should preferably be thin enough so as not toappreciably modify the gauging or fit of the cartridge in the chamber.It is not so essential that the coating cover the base of the cartridgs,but it is desirable that it should cover and envelop the mouth, neck andshoulder of the case and adjacent portions at which places seasoncracking first appears. The coating may with advantage seal the jointbetween the mouth of the case and the bullet to prevent the intrusion ofmoisture thereat.

Various methods of applying the wax coating to the ease of the cartridgemay be resorted to, but the method which I at present prefer is toliquefy the war; by obtaining a solution of the same in one of itssolvents and to dip the cartridges in a bath of the same. Ceresin issoluble in carbon disulphide as Well as carbon tetrachloride, but thelatter solvent is preferable because its smell is less obnoxious and itis noninflammable Whereas carbon bisulphide is highly inflammable anddangerous to use on that account. Carbon tetrachloride also will veryquickly evaporate from the solution.

After obtaining a suitable solution of the wax or ceresin, the cartridgemay be dipped in a bath of the same, bullet end down, so as to immersethe same up to a point adjacent the base of the cartridge, thus enveloping substantially all of the cartridge except the base. Thisdipping causes a thin film of wax solution to adhere to the cartridgeand upon Withdrawal of the latter the film Will quickly dry and hardendue to the rapid evaporation of the solvent. If it is desirable toaccelerate the drying and hardening of the film, an air blast may beemployed.

The thickness of the hardened film which finally dries upon thecartridge will depend principally upon the percentage of Wax in thesolution but, of course, this thickness may also be increased byrepeated dippings and hardening operations. In the present process, Ipreferably dip the cartridge once for a very short time in a 7% solutionof ceresin in carbon tetrachloride; that is, the ceresin forms but 7% ofthe liquid bath. The temperature of the bath solution is maintainedpreferably at approximately C.

I have described the preferred method of carrying out my invention and apreferred embodiment of the product thereof, but I Wish it to beunderstood that various modifications thereof and changes therein may beresorted to Without departing from the scope of the invention ashereinafter claimed.

What I claim is:

l. A cartridge comprising a case of drawn metal coated With an extremelythin film of hardened ceresin, adapted both as a protective covering forsaid case against a corrosion and for lubrication of said'case, saidcoating film being the air dried product rev sulting from an applicationto said case of a solution of ceresin in carbon tetrachloride. 2. Acartridge comprising a case of drawn metal coated with an extremely thinfilm of hardened ceresin, adapted both as a protective covering for saidcase against cor-' rosion and for lubrication of said case, said coatingfilm'being the air dried product resulting from an application to saidcase of a solution of ceresin in carbon tetrachloride, the concentrationof said solution being approximately 7% ceresin at a temperature. ofsaid solution of approximately 50 C.

In testimony whereof I have affixed my signature.

JOHN D. PEDERSEN.

